1. Field of the Invention
This invention relates to an arrangement for enhancing the steering effect of ships' rudders, comprising at least one passageway for supplying seawater from a pump to ducts in the rudder, and means communicating with the ducts and being adapted to discharge seawater supplied through them, at the rudder surface.
2. Description of the Related Art
Previously there are known many forms of steering effect enhancing means or elements in connection with ships' rudders. In particular at relatively low speeds such enhanced steering effect can be very useful when manoeuvring a ship.
A known form of such means are flaps or fins being hinged or pivotable in relation to the main part of the rudder, in particular being located at the trailing edge thereof. An example of such a design is to be found in Norwegian Patent 160.126.
Another form of auxiliary means are ports or nozzles in or at the rudder surface and being adapted to discharge water flows that can contribute to enhancing the steering effect of the rudder. Examples of such designs can be found in British patent 1.309.387 and Japanese patent publications Nos. 57.110.597, 57.110.598 and 57.121.998. These various designs are in part based on the supply of seawater to the rudder and its discharge openings or nozzles, through the actual rudder stock. However, there are also described designs where the seawater inlet and the transfer to the ports or openings takes place in a passive manner, i.e. without the influence of any pump which can impart energy to the seawater flow in the form of an increase pressure or velocity.